JP3886415B2 - Spark plug and burner - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a spark plug provided in a burner of a combustion apparatus such as a gas appliance or a boiler, and a burner provided with the spark plug.
[0002]
[Prior art]
Conventionally, as a spark plug provided in a burner such as a gas appliance, a center electrode (spark bar) embedded in an insulator such as an insulator provided inside a plug holder, and a small gap at the tip of the center electrode by bending the tip. An outer electrode opposed to the center electrode, and a high voltage is applied to the center electrode to generate a spark between the outer electrode and a fuel-air mixed fluid injected from the burner nozzle by the spark. Those that are designed to ignite are known.
[0003]
[Problems to be solved by the invention]
However, the spark generated by the spark plug is a small one that is limited to the vicinity of both electrodes. Under poor ignition conditions where the wind blows strongly, the spark burns into the gas burner mixed fluid. It is difficult to ignite because no sparks arrive. In particular, in the case of a large burner, the distance from the burner nozzle to the spark generation portion of the spark plug is considerably large, and therefore there is a problem that ignition is not easy.
[0004]
The present invention has been made in view of the above circumstances, and an ignition plug capable of generating a spark generated by an ignition plug in a wide range and reliably igniting fuel injected from a nozzle of a burner, and the ignition plug It aims at providing the burner which applied.
[0005]
[Means for Solving the Problems]
The present invention is characterized by the following points in order to solve the above problems.
That is, the spark plug according to claim 1 includes a cylindrical plug holder, an extension pipe connected to the tip of the plug holder with a screw, and one of the extension pipes screwed to the tip of the extension pipe . A cylindrical stabilizer as an electrode and a plug body screwed to and attached to the base end of the plug holder are supported via an insulator, inserted into the plug holder , the extension pipe, and the stabilizer, and the tip In the spark plug including the spark rod as the other electrode protruding forward from the tip of the stabilizer, an annular space is provided between the extension pipe and the stabilizer and the spark rod, and the annular space is provided in the annular space. gas introduction hole that fed gas flowing to the front end side of the spark rod is characterized by being et provided in the plug holder.
[0006]
According to a second aspect of the present invention, there is provided a spark plug according to the first aspect, wherein the stabilizer is formed in a tapered hole having a tapered inner side.
A spark plug according to claim 3 is the spark plug according to claim 1 or 2, wherein the gas is a mixed gas of fuel and air.
[0007]
According to a fourth aspect of the present invention, an inner cylinder is provided by opening an annular space for introducing combustion air inside the outer cylinder, and fuel supplied from a fuel supply pipe is mixed with the combustion air in the annular space. The burner is provided with a nozzle that injects into the combustion part in the inner cylinder, and is provided with a spark plug for igniting the fuel injected from the nozzle with the tip part positioned in front of the nozzle in the combustion part. The spark plug is attached to the cylindrical plug holder, the cylindrical stabilizer as one electrode attached to the tip of the plug holder, and the base end of the plug holder via an insulator. A spark rod as the other electrode that is inserted into the plug holder and the stabilizer and has a tip protruding forward from the tip of the stabilizer. To Heather, that combustion air introduced into the annular space between the outer cylinder and the inner cylinder is a gas introduction hole is found provided that flows into the annular space provided between the stabilizer and the spark rod It is characterized by.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a spark plug 1 according to an embodiment of the present invention will be described with reference to FIG.
The spark plug 1 includes a cylindrical (cylindrical) plug holder 2 made of a material such as brass having a shaft hole 2a, and a tip end portion (left end portion in FIG. 1) of the plug holder 2 via a screw ring 3a. A cylindrical (tubular) extension pipe 3 made of a material such as stainless steel having a shaft hole 3b communicating with the shaft hole 2a, and screwed to and connected to the tip of the extension pipe 3, A cylindrical (tubular) stabilizer 4 made of the same material as that of the extension pipe 3 having a shaft hole 4a communicating with the shaft hole 3b, and a screw provided at a base end portion (right end portion in FIG. 1) of the plug holder 2 And a spark bar 6 made of stainless steel or the like supported by a plug body 5 screwed into the hole 2b.
[0009]
The spark bar 6 forms one electrode of the spark plug 1, and the base end side (the right end side in FIG. 1) is an insulating member (not shown) such as an insulator inside the plug body 5. The tip end side (the left end side in FIG. 1) is forward of the tip end of the stabilizer 4 through the shaft hole 2a, 3b, 4a of the plug holder 2, the extension pipe 3, and the stabilizer 4 (FIG. 1). And a plug terminal 5a connected to the ignition coil is provided at the base end (right end in FIG. 1).
[0010]
Further, the spark rod 6 is supported by a spacer 7 made of an insulating material such as an insulator attached to the shaft hole 4a of the stabilizer 4 in the vicinity of the tip thereof, and is centered on the shaft center of each of the shaft holes 2a, 3b, 4a. Between the spark rod 6 and each of the shaft holes 2a, 3b, 4a, an annular space 8 having a predetermined interval is provided.
The plug holder 2 is provided with a gas introduction hole 2 c formed of a screw hole for feeding a gas such as air into the annular space 8.
[0011]
The spacer 7 is provided with a plurality of through holes 7 a in the circumferential direction communicating with the shaft hole 3 b of the extension pipe 3 and the tapered taper hole 4 b formed on the tip end side of the stabilizer 4.
Note that the outer periphery on the tip end side of the stabilizer 4 is also tapered. Further, in FIG. 1, 9 is a protective tube made of an insulating material covering the outer peripheral portion excluding the tip end side of the spark bar 6, and 2d is a male screw portion for screwing and attaching the spark plug 1 to the burner.
[0012]
When the spark plug 1 having the above-described configuration is used for a gas burner or the like, the spark plug 1 is attached to the gas burner or the like through a male screw portion 2d so as to face a position in front of the nozzle for injecting the fuel gas (fuel). A pipe or the like for sending combustion air or outside air is connected to the gas introduction hole 2 c of the holder 5, and an ignition coil is connected to the plug terminal 5 a of the plug body 5 of the ignition plug 1. And when igniting a gas burner or the like, by operating an ignition switch or the like, a mixed gas is injected from the nozzle of the gas burner and the combustion air or outside air is sent from the gas introduction hole 2c by a blower or the like, The ignition coil is energized to apply a high voltage to the spark bar 6 through the plug terminal 5a to generate a spark with the tip of the stabilizer 4.
[0013]
At this time, the air introduced into the plug holder 2 from the gas introduction hole 2 c passes through the annular space 8 and is squeezed by the tapered taper hole 4 b of the stabilizer 4, and from the opening along the tip of the spark bar 6. Since it is ejected, the generated spark spreads large and well along the tip side of the spark rod 6 and can reliably reach the portion of the mixed gas ejected from the nozzle of the gas burner. This ensures that sparks can be brought into contact with the fuel injected from the nozzle even without a failure even under bad conditions such as a large gas burner or a wind blowing on the burner's combustion part. The mixed gas can be ignited.
[0014]
The air flowing into the annular space 8 varies depending on the size of the annular space 8, the diameter of the tip opening of the stabilizer 4, and the like, but the flow rate is preferably set in the range of 5 m / s to 40 m / s.
Even when the fuel is ignited and burned, air is continuously fed into the annular space 8, so that the air ejected from the front end opening of the stabilizer 4 causes the front end of the stabilizer 4 and the front end of the spark bar 6 to move. There is no possibility that these parts are cooled and heated to a high temperature by combustion heat of a gas burner or the like and burned out, and the life of the stabilizer 4 and the plug rod 6 can be extended.
[0015]
Next, a spark plug 10 according to another embodiment of the present invention and a gas burner 11 according to an embodiment of the present invention to which the spark plug 10 is applied will be described with reference to FIGS.
The gas burner 11 is closed at both ends, and has a cylindrical outer cylinder 12 provided with an air supply pipe 12a on one side (lower side in FIGS. 1 and 2), and an annular space a inside the outer cylinder 12. A cylindrical inner cylinder 13 that is provided concentrically by opening, a nozzle 14 that is provided concentrically by opening an annular space b in the inner cylinder 13, and a fuel supply pipe 15 that introduces fuel gas into the nozzle 14. It has.
[0016]
The inner cylinder 13 has an opening 13a at one end fixed to the closing wall 12b at one end of the outer cylinder 12 and protrudes from the closing wall 12b, and the closing wall 13b at the other end is outside. A space c is provided between the tube 12 and the closed wall portion 12c on the other end side, and the closed end portion 13b has a plurality of air holes 13c communicating with the annular space b at appropriate intervals in the circumferential direction. Is provided. The nozzle 14 is fitted with a nozzle plate 14a which is formed in a net shape with a heat-resistant metal at one end (right end in FIG. 2) and has a large number of vent holes, and the other end is a closed wall portion of the inner cylinder 13. It is attached to 13b.
The fuel supply pipe 15 is inserted into the nozzle 14 through the closed wall portion 12c of the outer cylinder 12, and has an injection head 15a provided with an injection hole around the inner end portion for injecting fuel gas into the nozzle 14. Is provided.
[0017]
The spark plug 10 has a cylindrical (cylindrical) plug holder 16 made of a material such as brass having a shaft hole 16a, and the plug holder 16 on the front end side of the shaft hole 16a (the lower end side in FIGS. 2 and 3). ) Of the large-diameter shaft hole portion 16b is fitted and connected to the base end portion side, and is cylindrical (tubular) as an electrode made of a material such as stainless steel having a shaft hole 17a communicating with the shaft hole 16a. A stabilizer 17 and a spark bar 18 as an electrode provided to be supported by a base end portion (upper end portion in FIG. 1) of the plug holder 16 are provided.
[0018]
The plug holder 16 has a male threaded portion 16c1 of the small-diameter cylindrical portion 16c on the tip side in a screw hole of a mounting seat 12d provided on the other side portion (upper portion in FIGS. 2 and 3) of the outer cylinder 12 of the gas burner 11. It is screwed together and attached to the outer cylinder 12 with its front end surface abutting against a receiving seat 13d provided on the inner cylinder 13. The small diameter cylindrical portion 16c of the plug holder 16 has a plurality of through holes (gas introduction holes) 16e communicating with the annular space a of the gas burner 11 and the large diameter shaft hole 16b of the shaft hole 16a in the circumferential direction. Opened. Further, the contact portion between the step portion of the small diameter cylindrical portion 16c of the plug holder 16 and the seat surface of the mounting seat 12d and the contact portion between the tip end surface of the plug holder 16 and the receiving seat 13d are respectively provided with a heat resistant material. Seal seals 19a, 19b made of metal are attached.
[0019]
The stabilizer 17 has a distal end side (lower end side in FIGS. 2 and 3) formed with a tapered taper at the outer peripheral portion, and protrudes into the inner cylinder 13 through the inside of the receiving seat 13d of the gas burner 11, The tip portion is located in the vicinity of the front side of the nozzle 14 (to the right in FIG. 2) and close to the extended surface of the outer periphery of the nozzle 14. Further, the shaft hole 17a of the stabilizer 17 is a tapered hole 17b that is tapered at the tip end side, and the phase in the circumferential direction and the axial direction are aligned with the through-hole 16e at the approximate center in the axial direction of the stabilizer 17. A through hole (gas introduction hole) 17c provided in communication with the annular space a through the through hole 16e. Furthermore, a cylindrical spacer 20 made of an insulating member such as an insulator having a shaft hole 20a in a section between the tapered hole 17b and the through hole 17c is fitted into the shaft hole 17a of the stabilizer 17.
[0020]
The spark bar 18 is fixed to the center of a cylindrical holder 21 made of an insulating member such as an insulator, and the tip end side (the lower end side in FIGS. 2 and 3) is exposed from the insulator so that the spacer 20 It protrudes from the stabilizer 17 into the inner cylinder 13 of the gas burner 11 through the shaft hole 20a and the taper hole 17b, and its tip extends from the extension of the outer periphery of the nozzle 14 of the gas burner 11 to a position closer to the center of the nozzle 14. ing. The holding body 21 has a nut 22 fixed to the base side (the upper side in FIGS. 2 and 3), and is supported by the plug holder 16 by screwing the nut 22 into the screw hole 16 b of the plug holder 16. As a result, the spark bar 18 is positioned at the center of each shaft hole 17a, 20a, taper hole 17b of the stabilizer 17, spacer 20, and the spark bar 18, each shaft hole 17a, 20a, taper hole 17b. An annular space d opened at the tip of the stabilizer 17 is formed between the inner surface and the inner surface, and the annular space d communicates with the annular space a through the through holes 17c and 16e.
A plug terminal 23 connected to the ignition coil is provided at the base end portion (the upper end portion in FIGS. 2 and 3) of the spark bar 18.
[0021]
When the gas burner 11 according to the above embodiment is ignited, an ignition switch or the like is operated to send fuel gas to the fuel supply pipe 15 and to send combustion air into the outer cylinder 12 from the air supply pipe 12a. When power is supplied to the ignition coil at the same time, a high voltage is applied to the spark rod 18 via the plug terminal 23 of the spark plug 10, and a spark is generated between the tip of the stabilizer 17. The At this time, combustion air is inserted into the annular space a in the outer cylinder 12 from the air supply pipe 12a by a blower or the like, and the fuel gas injected into the nozzle 14 from the injection head 15a and the space c from the annular space a. Since the mixed gas (fuel) mixed with the combustion air that has entered the nozzle 14 via the nozzle 14 is injected from the nozzle plate 14a of the nozzle 14 to the combustion portion 11a in the front (on the spark plug 10 side), The spark comes into contact with the jetted mixed gas and ignites the mixed gas. The ignited mixed gas is combusted by the combustion air flowing forward from the vent hole 13c of the inner cylinder 13 through the annular space b.
[0022]
According to the gas burner 11 according to the embodiment, the combustion air that has entered the annular space a in the outer cylinder 12 from the air supply pipe 12a is passed through the through hole 16e of the plug holder 16 of the spark plug 10 and the stabilizer 17. Since the air enters the annular space d in the stabilizer 17 through the through-hole 17c and is blown out from the opening at the tip of the stabilizer 17, the spark generated between the spark rod 18 and the stabilizer 17 is generated at the tip of the spark rod 18. It spreads greatly along the side and can reach the part of the mixed gas injected from the nozzle 14 of the gas burner 11 with certainty. Thereby, similarly to the case where the spark plug 1 according to the above-described embodiment is used, the mixed gas injected from the nozzle 14 can be reliably ignited even under a condition where the ignition condition is bad.
[0023]
In addition, in the spark plug 10 attached to the gas burner 11, the stabilizer 17 and the spark bar 18 are cooled by the combustion air flowing in the annular space d of the stabilizer 17, similarly to the spark plug 1 according to the embodiment. Thus, it is possible to prevent the electrodes 17 and 18 from being overheated to a high temperature by the combustion heat of the gas burner 11 and being burned out. In addition, the combustion air of the gas burner 11 can be introduced into the annular space d of the stabilizer 17 from the annular space a in the outer cylinder 12 in the gas burner 11, so that air is separately sent into the annular space d. No piping is required, the structure is simple, and manufacturing is easy.
[0024]
Although the description has been given of the case where the spark plug 1 according to the embodiment is provided in the burner and used as the spark plug for igniting the fuel injected from the nozzle of the burner, the present invention is not limited to this. , flowing said ignition fuel into the annular space 8 of the plug 1 and the air and the mixed fluid, ignition spark for generating the mixed fluid between the spark rod 6 and the stabilizer 4, by burning, the spark plug 1 itself It can be used effectively as a burner.
[0025]
In the gas burner according to the above embodiment, the combustion air for premixing with the fuel gas in the nozzle 14 is fed into the annular space d of the spark plug 10, but the present invention is not limited to this. Combustion air for mixing with the fuel from the nozzle 14 may be sent into the annular space d by the combustion part 11a in front of the nozzle 14 . Also, in the above, the present invention has been described as being applied to a gas burner for burning a fuel gas, the present invention can be applied is not limited to this, the liquid fuel burner for burning liquid fuel.
[0026]
【The invention's effect】
As described above, according to the present invention, the following excellent effects can be obtained.
According to the spark plug according to claim 1, since the annular space is provided between the stabilizer and the spark rod, and the gas flowing to the tip side of the spark rod is sent into the annular space, By flowing a gas such as air through the annular space, the spark generated between the spark rod and the stabilizer can be greatly spread along the spark rod to the tip side thereof, and fuel injected from the nozzle of the burner It can be ignited easily by making sure that it comes into contact with. Further, the stabilizer and the spark rod can be cooled by the gas flowing in the annular space, and the electrodes can be prevented from being overheated to a high temperature by the combustion heat of the burner and being burned out.
[0027]
According to the spark plug of the second aspect, since the stabilizer is formed in a tapered hole whose inside is tapered, the gas flowing in the annular space of the spark plug can easily flow along the spark rod, and the tip of the spark rod The spread of the spark to the side can be further improved.
According to the spark plug of the third aspect, since the fluid mixture of fuel and air is fed into the annular space of the spark plug, the spark plug can be used effectively as a burner.
[0028]
According to the burner according to claim 4, the fuel supplied from the fuel supply pipe is mixed with the combustion air by the nozzle and then injected into the combustion portion of the burner, and the annular space between the stabilizer of the spark plug and the spark rod In addition, since the combustion air of the burner is configured to be sent in, the ignitability of the mixed fluid of fuel and air can be improved, and the stabilizer and the spark bar are moved by the air flowing in the annular space. By being cooled, the electrodes can be prevented from being overheated to a high temperature by the combustion heat of the burner and burning. Moreover, since the combustion air of the burner can be introduced into the annular space in the burner, there is no need for a separate pipe for introducing air into the annular space, the structure is simplified, and the manufacture is easy.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing a spark plug according to an embodiment of the present invention.
FIG. 2 is a longitudinal sectional view showing a burner according to an embodiment of the present invention.
3 is a cross-sectional view taken along line XX in FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1,10 Spark plug 2,16 Plug holder 2c Gas introduction hole 3 Extension pipe 4,17 Stabilizer 4a, 17b Taper hole 5, Plug main body 6,18 Spark rod 8 Annular space 11 Gas burner 12 Outer cylinder 12a Air supply pipe 13 Inner cylinder 14 Nozzle 15 Fuel supply pipe 16e, 17c Through hole (gas introduction hole)
21 holding body 23 plug terminals a, b, c, d annular space

Claims (4)

A cylindrical plug holder, an extension pipe connected to the tip of the plug holder with a screw, a cylindrical stabilizer as one electrode screwed and connected to the tip of the extension pipe, and the plug It is supported via an insulator on the plug body that is screwed onto the base end of the holder, inserted through the plug holder , extension pipe, and stabilizer, and the tip protrudes forward from the tip of the stabilizer. In a spark plug with a spark rod as the other electrode,
It is between the spark rod and the extension pipe and the stabilizer is provided an annular space, the gas introduction hole that fed gas flowing to the front end side of the spark rod to the annular space is found provided on the plug holder Spark plug characterized by.   The spark plug according to claim 1, wherein the stabilizer is formed in a tapered hole having a tapered inner side.   The spark plug according to claim 1 or 2, wherein the gas is a mixed gas of fuel and air. An inner cylinder is provided with an annular space for introducing combustion air inside the outer cylinder, and fuel supplied from a fuel supply pipe is mixed with the combustion air in the annular space to form a combustion portion in the inner cylinder. A burner provided with a nozzle for injecting, and provided with a spark plug for igniting fuel injected from the nozzle by positioning a tip portion in front of the nozzle in the combustion section;
The spark plug is a cylindrical plug holder, a cylindrical stabilizer as one electrode attached to the tip of the plug holder, and attached to the base end of the plug holder via an insulator, And a spark rod as the other electrode inserted through the plug holder and the stabilizer and projecting the tip portion forward from the tip of the stabilizer, and provided on the stabilizer between the stabilizer and the spark rod. burner, characterized in that the gas introduction hole that combustion air introduced into the annular space between the outer cylinder and the inner tube into the annular space flows are al provided.

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